Understanding and preparing for the EPA’s proposed PFOA and PFOS compliance extension rule

On May 18, 2026, the EPA announced a proposed rule to allow public water systems (PWS) to seek a federal exemption for two additional years to comply with the Maximum Contaminant Levels (MCLs) for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). The extension will shift the compliance date from April 26, 2029 to April 26, 2031 for approved systems.

While this extension is possible under the exemption provision in Section 1416 of the Safe Drinking Water Act (SDWA), the process is unprecedented and could cause confusion and more regulatory uncertainties for PWS.

So far, nine states have initiated state-level rulemaking to incorporate the new PFOA and PFOS drinking water standards and have submitted a primacy program revision application to EPA for approval. These states include Vermont, Illinois, Maryland, Connecticut, Colorado, Washington, Wisconsin, Idaho, and North Carolina. Once a state obtains primacy for the NPDWR for PFAS, EPA can no longer grant federal exemption to PWS to extend the compliance deadline.

What Is State Primacy for EPA Drinking Water Regulations?

Primacy is the primary enforcement responsibility delegated by the EPA to a state, territory, or federally recognized tribe to implement and enforce federal drinking water regulations. States with primacy enforce the drinking water regulations and oversee the local water systems. In contrast, EPA has enforcement authority for states without primacy (Wyoming and District of Columbia). Therefore, PWS will need to factor in the state’s primacy status when deciding whether to pursue EPA’s exemption.

How State Primacy Could Affect the Proposed PFOA and PFOS Compliance Extension

Because of the timing of this rule, states will be working with EPA to establish primacy for the PFAS NPDWR at the same time that water systems may be applying for an extension. This situation can create confusion regarding who (EPA or states) has authority to implement this rule during the transition phase. Water systems are advised to work closely with state primacy agencies for guidance on which agency should make the final decision on the approval and duration of the extension.

What Public Water Systems Must Do During the Compliance Extension

Under the proposed rule, PWS seeking a compliance extension that have one PFOA or PFOS sample result at or above 12 ng/L would be required to choose and implement at least two out of six control measures during the exemption period to minimize public exposure to PFOA and PFOS.

The six control measure options include:

1. Providing water pitchers and two-year supply of filters certified to reduce PFOA and PFOS levels;
2. Delivering alternative water supplies with lower levels of PFOA and PFOS, by distributing bottled water, temporarily switching to a new source with lower levels of PFOA and PFOS, or blending of water supplies to reduce PFOA and PFOS concentrations;
3. Installing, operating, and maintaining point-of-use (POU) or point-of-entry (POE) devices certified in every customer location to decrease PFOA and PFOS levels;
4. Implementing actions and plans to decrease PFOA and PFOS levels in drinking water sources;
5. Distributing written public education materials to consumers on PFOA and PFOS exposure sources; and
6. Conducting community education and outreach activities on PFOA and PFOS in drinking water.

EPA is proposing that the two control measures selected cannot solely include public education materials and public outreach activities (options 5 and 6).

If a PWS seeking a compliance extension has PFOA and PFOS levels above the MCLs of 4.0 ng/L but below 12 ng/L, NO control measures would be required during the exemption period.

Preparing for EPA’s Proposed PFOA and PFOS Compliance Extension

1. Engage early and often with your state primacy agency. States will play the central role in enforcing the NPDWR for PFAS and ultimately decide if they want to allow for the federal exemption. Once states obtain primacy, they may choose to shorten or end an exemption granted by EPA. Early engagement can clarify expectations and reduce uncertainty.
2. Submit written comments on the proposed rule in the public docket until July 20, 2026. Attend the virtual public hearing hosted by EPA on July 7, 2026 to provide verbal comments.
3. Continue advancing treatment planning and implementation. Do not pause or delay technology evaluation, system design, construction, or system commissioning.
4. For capital improvement projects, consider alternative project delivery approaches and advance early work packages or pre-procurement strategies to secure long-lead items and reduce schedule risk.
5. Plan for interim actions. Utilities may need to identify and implement interim measures, such as raw water blending, powdered activated carbon (PAC) application, and other available tools and communicate with state primacy agency and customers about these interim control strategies.
6. Establish a public communication and outreach plan. Seeking a compliance extension requires formally certifying noncompliance, which carries public perception risks.

Carollo Can Help Plan for PFOA and PFOS Compliance

Our team can support PWS through each step of the process, from drafting and submitting comments on the proposed rule; coordinating with regulators for compliance approvals, including the two-year extension; testing, designing, and constructing treatment systems; and providing public outreach support.